Abstract:

A lens holder (16) is attached to a processing target lens (2) such that a
holder center (O) coincides with a processing center position (21) of the
lens. An axial deviation measuring mark (81a, 81b) is displayed on the
processing target lens (2) to coincide with a reference position mark
(80a, 80b) of the lens holder (16), and the circumferential surface of
the processing target lens (2) undergoes primary processing. After
primary processing, the axial deviation of the processing target lens (2)
is measured from the reference position mark (80a, 80b) and axial
deviation measuring mark (81a, 81b). When axial deviation exists, the
lens holder (16) is removed from the processing target lens (2) and the
processing target lens (2) is held again, so that the axial deviation is
corrected. After that, the processing target lens (2) undergoes secondary
processing.

Claims:

1. A spectacle lens edging method comprising the steps of holding a
processing target lens by lens holding means, mounting the lens holding
means on a lens rotating shaft together with the processing target lens,
processing a circumferential surface of the processing target lens using
a processing tool by primary processing, correcting axial deviation of
the processing target lens having undergone primary processing, and
processing the axial deviation-corrected processing target lens by
secondary processing,the step of holding the processing target lens by
the lens holding means further comprising the steps of holding the
processing target lens such that a center of the lens holding means
coincides with a processing center of the processing target lens, and
displaying an axial deviation measuring mark on one optical surface of
the processing target lens so as to coincide with a reference position
mark displayed on the lens holding means, andthe step of correcting the
axial deviation of the processing target lens having undergone primary
processing comprising the axial deviation measuring step of removing the
processing target lens from the lens rotating shaft together with the
lens holding means after primary processing and measuring axial deviation
of the processing target lens from the reference position mark and the
axial deviation measuring mark, the axial deviation correcting step of
correcting the axial deviation of the processing target lens which is
measured by the axial deviation measuring step by holding one optical
surface of the processing target lens with the lens holding means again
such that the axial deviation measuring mark coincides with the reference
position mark, and the step of mounting the lens holding means on the
lens rotating shaft again together with the processing target lens.

2.-3. (canceled)

4. A spectacle lens edging method according to claim 1,wherein a primary
shape of the processing target lens processed by the primary processing
step is either one of a circle larger than a circle inscribed by an edged
lens shape that complies with a frame shape of a spectacle frame and an
edged shape similar to and larger than the edged lens shape that complies
with the frame shape, and a secondary shape of the processing target lens
processed by the secondary processing step is either one of an edged lens
shape that complies with the frame shape of the spectacle frame and an
edged lens shape slightly larger than the edged lens shape that complies
with the frame shape.

5. (canceled)

6. A spectacle lens edging method according to claim 1,wherein the axial
deviation measuring step for the processing target lens is performed by
either one of image processing and visual measurement.

7. (canceled)

8. A spectacle lens edging method according to claim 1,wherein the
reference position mark is displayed either one of before holding the
processing target lens and simultaneously with displaying the axial
deviation measuring mark on an unprocessed lens.

Description:

[0002]When fabricating a spectacle lens having an edged lens shape
complying with the frame shape of a spectacle frame by grinding the
circumferential surface of an unprocessed round lens (to be also referred
to as an uncut lens or a processing target lens hereinafter), if the lens
is held with a weak force, the processing resistance applied by a
grinding stone may cause axial deviation of the lens. More specifically,
the processing center position of the actual lens may deviate from the
lens rotating shaft. The axial deviation of the lens appears in a
direction (radial direction) perpendicular to the processing center
position when the lens does not have a cylinder axis, and includes
deviation in the direction perpendicular to the processing center
position and deviation in the rotational direction with respect to the
processing center position when the lens has a cylinder axis. To solve
this problem, conventionally, various methods have been proposed such as
increasing the lens holding force, or employing an edging apparatus, an
edging method, and an adhesive tape as described in Japanese Patent
Laid-Open Nos. 2003-300138, 11-333684, 11-333685, 2002-182011, and
2004-122302.

[0003]The lens processing method and processing apparatus described in
Japanese Patent Laid-Open No. 2003-300138 improve the processing accuracy
of the circumferential surface of a lens without requiring in advance the
design data of the lens to be finished. Hence, according to this lens
processing method, the processing target lens is roughly processed based
on the lens frame shape data of a spectacle frame or shape data that can
comply with a spectacle, and thereafter the shape of the lens is
measured. Then, the lens is finished to a shape complying with the shape
of the spectacle frame or a shape complying with the spectacle based on
the rough processing shape data obtained by the measurement.

[0004]The spectacle lens processing apparatus described in Japanese Patent
Laid-Open No. 11-333684 processes a lens highly accurately by preventing
axial deviation, breaking of the lens, and coat cracking. For this
purpose, this spectacle lens processing apparatus includes a first lens
chuck shaft on which a processing target lens is mounted through a fixing
cup, a second lens chuck shaft which is arranged coaxially with the first
lens chuck shaft and on which a lens retaining member to retain the
processing target lens is attached, a rotational deviation detection
means for detecting the deviations of the rotation angles of the lens
chuck shafts, and a process control means which processes the processing
target lens based on the detection result obtained by the rotational
deviation detection means.

[0005]The spectacle lens processing apparatus described in Japanese Patent
Laid-Open No. 11-333685 allows processing a processing target lens under
appropriate conditions in accordance with the shape of the lens under
processing. To achieve this, according to the spectacle lens processing
apparatus, an encoder provided to a servo motor detects the travel amount
(the shaft-to-shaft distance between a lens chuck shaft and the rotating
shaft of a grinding wheel) of a carriage. An obtained detection signal is
sent to a controller. The controller measures the during-processing shape
corresponding to the rotation angle of the lens from an input signal. The
processing pressure (the preset value of the rotary torque) is changed to
correspond to the during-processing shape. More specifically, when the
lens chuck shaft is distant from a processing end portion, the process is
started after decreasing the processing pressure by lowering the
carriage. As the distance to the processing end decreases, the processing
pressure is increased gradually. When the processing pressure is changed
depending on a lens processing diameter in this manner, axial deviation
can be suppressed, and highly accurate processing can be performed.

[0006]According to the technique described in Japanese Patent Laid-Open
Nos. 2002-182011 and 2004-122302, a double-coated adhesive tape or a
coating film is formed between a processing target lens and a lens
holding means, so that slipping is prevented.

DISCLOSURE OF INVENTION

Problem to be Solved by the Invention

[0007]In recent years, a spectacle lens with an optical surface on which a
water-repellent film layer is formed to improve the repellency of the
lens is becoming popular, as disclosed in, e.g., Japanese Patent
Laid-Open No. 2004-122238. When edging a processing target lens which has
such a water-repellent film layer, because of the presence of the
water-repellent film layer, the optical surface of the lens is much
smoother than that of any other currently available lens. More
specifically, since the lens surface is slippery, with the conventional
processing apparatus as described in Japanese Patent Laid-Open Nos.
2003-300138, 11-333684, or 11-333685, it is difficult to hold the lens
reliably. During edging, slipping occurs between the lens holding means
and the lens, making it difficult to process the processing target lens
into a predetermined edged lens shape. Particularly, when the lens is a
minus-power lens having a high dioptric power, as the peripheral edge is
very thick, the processing resistance at the start of processing is large
and axial deviation occurs easily. As a result, it is difficult to
process the lens highly accurately.

[0008]When adopting the methods of preventing axial deviation which
increase the lens holding force by employing the adhesive tape or forming
the coating film described in Japanese Patent Laid-Open Nos. 2002-182011
and 2004-122302, if air enters between the lens surface and the tape or
coating film, it decreases the lens holding force. If the lens has high
lubricating properties or the peripheral edge of the lens has a
relatively large thickness, axial deviation cannot be prevented
completely.

[0009]When the method of increasing the lens holding force is employed, it
may break the lens itself or damage the coating film formed on the lens
surface. Thus, this method has limitations in increasing the holding
force.

[0010]The present invention has been made to solve the above conventional
problems, and has its object to provide a spectacle lens edging method
which can produce a highly accurate spectacle lens eventually free from
axial deviation even from a stainproof lens having a high lubricating
properties or a lens having relatively thick peripheral edge.

Means of Solution to the Problems

[0011]In order to achieve the above object, according to the present
invention, there is provided a spectacle lens edging method comprising
the steps of holding a processing target lens by lens holding means,
mounting the lens holding means on a lens rotating shaft together with
the processing target lens, and processing a circumferential surface of
the processing target lens using a processing tool by primary processing
and secondary processing, the step of holding the processing target lens
by the lens holding means further comprising the steps of holding the
processing target lens such that a center of the lens holding means
coincides with a processing center of the processing target lens, and
displaying an axial deviation measuring mark on one optical surface of
the processing target lens so as to coincide with a reference position
mark displayed on the lens holding means, and the method further
comprising the step of correcting axial deviation of the processing
target lens after primary processing.

EFFECT OF THE INVENTION

[0012]According to the present invention, in a primary processing step,
axial deviation is measured after processing the lens with no specific
axial deviation preventive countermeasures. If axial deviation is
observed, it is corrected by holding the lens correctly with the lens
holding means, and thereafter secondary processing is performed. Thus,
axial deviation in secondary processing can be prevented. More
specifically, as primary processing includes edging an uncut lens, the
processing resistance is high at the start of processing. If the lens has
a large diameter or the lens has high lubrication properties due to a
water-repellent film layer, axial deviation tends to occur. In secondary
processing, the lens has a small diameter. Thus, the processing
resistance is low. Even if the lens has high lubrication properties or
the lens in primary processing is an uncut lens with a large diameter, it
need not be held with a particularly large lens holding force, and will
not cause axial deviation easily, in the same manner as a general lens.

BRIEF DESCRIPTION OF DRAWINGS

[0013]FIG. 1 is a schematic perspective view of an edging apparatus
employed in a spectacle lens edging method according to the present
invention;

[0014]FIG. 2 is a view showing a state in which a processing target lens
is mounted on a lens rotating shaft;

[0015]FIG. 3 is a perspective view showing how a lens holder is mounted on
the processing target lens;

[0016]FIG. 4 is a view showing how a lens shape measurement unit measures
the lens shape;

[0017]FIG. 5A is a view showing a state in which the lens holder is
mounted on the processing target lens;

[0022]FIG. 8 is a flowchart of edging according to another embodiment of
the present invention; and

[0023]FIG. 9 is a view showing how to measure the axial deviation of a
processing target lens.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024]The present invention will be described in detail based on
embodiments shown in the accompanying drawings.

[0025]Referring to FIGS. 1 to 5, a spectacle lens edging apparatus denoted
by reference numeral 1 is an apparatus to manufacture a spectacle lens 2A
(FIG. 5A) having a desired edged lens shape by edging a processing target
lens 2 formed of an unprocessed round lens, and includes a box-like
housing 3 installed on a floor surface. A lens rotating shaft 4, a first
lens rotating shaft moving mechanism 5, a second lens rotating shaft
moving mechanism 6, a processing tool 7, a rotational drive mechanism 8
for the processing tool 7, a controller (not shown), a lens shape
measurement unit 9, a chamfering mechanism 10 for the processing target
lens 2, and the like are built in the housing 3. The processing target
lens 2 is mounted on the lens rotating shaft 4 through a lens holding
means. The first lens rotating shaft moving mechanism 5 moves the lens
rotating shaft 4 in an axial direction (X direction). The second lens
rotating shaft moving mechanism 6 similarly moves the lens rotating shaft
4 in a horizontal direction (Y direction) perpendicular to the axis. The
processing tool 7 edges the processing target lens 2. The controller
controls the entire apparatus. The lens shape measurement unit 9 measures
optical surfaces 2a and 2b of the processing target lens 2. The upper
surface of the housing 3 is provided with an operation panel (not shown)
including a display and various types of operation buttons to input lens
information on the processing target lens 2, information on a spectacle
frame, processing conditions, and the like.

[0026]The processing target lens 2 is formed of a round (with a diameter
of, e.g., 80 mm) plastic minus-power lens formed by casting and
polymerization.

[0027]Examples of the optical base material of the processing target lens
2 include, e.g., a copolymer formed from methyl methacrylate and at least
another monomer, a copolymer formed from diethylene glycol bis(allyl
carbonate) and at least another monomer, and a vinyl copolymer containing
polycarbonate, urethane, polystyrene, polyvinyl chloride, unsaturated
polyester, polyethylene terephthalate, polyurethane, polythiourethane,
sulfide utilizing an enthiol reaction, or sulfur. Although a
urethane-based optical base material and an allyl-based optical base
material are particularly preferable among these base materials, the
present invention is not limited to them. The optical base material of
the present invention is preferably a plastic optical base material, and
more preferably a plastic optical base material for spectacles.

[0028]As shown in FIG. 6, a protective film layer 64 and water-repellent
film layer 67 are stacked on the entire surface of each of the optical
surfaces 2a and 2b of the processing target lens 2. The protective film
layer 64 is formed to improve the optical characteristics, durability,
resistance to marring, and the like of the lens, and ordinarily includes
a hard coat film layer 65 and antireflection film layer 66.

[0029]The lowermost hard coat film layer 65 is formed to enhance the
hardness of the spectacle lens itself and improve the resistance to
marring. As the material of the hard coat film layer 65, an organic
substance such as a silicon-based resin is used. The hard coat film layer
65 is formed by applying a silicon-based resin made of a solvent by
dipping or spin coating and curing the applied resin by heating in a
heating furnace. This method of forming the hard coat film layer 65 is
conventionally known well.

[0030]The antireflection film layer 66 as the intermediate layer is formed
to enhance the antireflection effect and the resistance to marring. The
antireflection film layer 66 is formed from a plurality of different
materials so it forms a multilayered antireflection film layer. As an
antireflecting material, for example, a metal oxide or silicon oxide of
Zr, Ti, Sn, Si, In, Al, or the like, or MgF2 is used. Such a
multilayered antireflection film layer 66 is formed by vacuum deposition
described in, e.g., Japanese Patent Laid-Open No. 11-333685 described
above.

[0031]The multilayered antireflection film layer 66 is preferably formed
by an ion-assisted deposition method so that it obtains a high film
strength and good adhesion. The layers that form films other than a
hybrid layer of the antireflection film are tantalum oxide
(Ta2O5) layers serving as high-refractive layers so that
physical properties such as a good antireflection effect and resistance
to marring can be obtained. Each tantalum oxide layer contains preferably
at least 50 wt % of tantalum oxide and more preferably 80 wt % or more of
tantalum oxide.

[0032]According to the ion-assisted deposition method, the preferable
output range of the acceleration voltage is 50 V to 700 V and that of the
acceleration current is 30 mA to 250 mA from the viewpoint of obtaining a
particularly good reaction. As an ionization gas used when practicing the
ion-assisted deposition method, argon (Ar) or a gas mixture of argon and
oxygen is preferably used in consideration of the reactivity and
oxidation prevention during film formation.

[0033]The inorganic substance used in the hybrid layer of the present
invention must include silicon dioxide and can include at least one
member selected from the group consisting of aluminum oxide, titanium
oxide, zirconium oxide, tantalum oxide, yttrium oxide, and niobium oxide.
When using a plurality of inorganic substances, they may be mixed
physically. Alternatively, the inorganic substance can be a composite
oxide, e.g., silicon dioxide (SiO2) or aluminum monoxide
(Al2O3). Among them, silicon dioxide alone and at least one
type of inorganic oxide selected from the group consisting of silicon
dioxide and aluminum oxide are preferable.

[0034]As the organic substance used to form the hybrid layer of the
present invention, an organic silicide which is liquid at normal
temperature and normal pressure and/or an organic compound not containing
silicon, which is liquid at normal pressure, is preferable from the
viewpoint of film thickness control and deposition rate control.

[0035]The organic silicide preferably has any one of the structures
represented by the following general formulas (a) to (d):

[0036]General formula (a): silane/siloxane compound

##STR00001##

[0037]General formula (b): silazane compound

##STR00002##

[0038]General formula (c): cyclosiloxane compound

##STR00003##

[0039]General formula (d): cyclosilazane compound

##STR00004##

[0040]In general formulas (a) to (d), m and n each independently represent
an integer of 0 or more. X1 to X8 each independently represent
hydrogen, a hydrocarbon group (including both saturated and unsaturated
hydrocarbon groups) having 1 to 6 carbon atoms, an --OR1 group, a
--CH2OR2 group, a --COOR3 group, an --OCOR4 group, an
--SR5 group, a --CH2SR6 group, an --NR72 group,
or a --CH2NR82 group [R1 to R8 each
independently represent hydrogen or a hydrocarbon group (including both
saturated and unsaturated hydrocarbon groups) having 1 to 6 carbon atoms.
X1 to X8 may be arbitrary ones of the above functional groups
and may all be the same or different.

[0043]Specific examples of the compound represented by general formula (b)
include 1,1,3,3-tetramethyldisilazane, hexamethyldisilazane, and
1,3-divinyl-1,1,3,3-tetramethyldisilazane.

[0044]Specific examples of the compound represented by general formula (c)
include hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane,
1,3,5,7-tetramethylcyclotetrasiloxane, and octamethylcyclotetrasiloxane.

[0045]Specific examples of the compound represented by general formula (d)
include 1,1,3,3,5,5-hexamethylcyclotrisilazane and
1,1,3,3,5,5,7,7-octamethylcyclotetrasilazane.

[0046]The number average molecular weights of these organosilicon
compounds fall within the range of preferably 48 to 600 and most
preferably 140 to 500 from the viewpoint of control of organic components
in hybrid films and the strengths of the films themselves.

[0047]A non-silicon-containing organic compound of the hybrid layer
includes preferably a compound containing hydrogen and carbon as
indispensable components and having a reactive group at its side chain or
terminal, and more specifically a compound represented by general
formulas (e) to (g).

[0048]General formula (e): non-silicon-containing organic compound
containing carbon and hydrogen as indispensable components and having an
epoxy group at one terminal

##STR00005##

[0049]General formula (f): non-silicon-containing organic compound
containing carbon and hydrogen as indispensable components and having
epoxy groups at two terminals

[0051]In general formulas (e) and (f), R9 represents hydrogen or a
hydrocarbon group which has 1 to 10 carbon atoms and may contain oxygen,
and R10 represents a divalent hydrocarbon group which has 1 to 7
carbon atoms and may contain oxygen. In general formula (g), X9 to
X12 each independently represent hydrogen, a hydrocarbon group
having 1 to 10 carbon atoms, or an organic group containing hydrogen and
carbon having 1 to 10 carbon atoms as indispensable components and at
least one of oxygen and nitrogen as an indispensable component.

[0055]The number average molecular weights of these compounds represented
by general formulas (e) to (g) fall within the range of preferably 28 to
4,000 and most preferably 140 to 360 in consideration of control of
organic components in hybrid films and the strengths of the films
themselves.

[0056]As a method of forming an organosilicon compound which is liquid at
normal temperature and normal pressure and/or a non-silicon-containing
organic compound (to be also referred to as an organic material
hereinafter) which is liquid at normal temperature and normal pressure,
it is preferable to simultaneously deposit hybrid films using different
vapor sources of inorganic and organic materials. More specifically, an
inorganic material is heated to evaporate using an electron gun or the
like. An organic material is stored in an external tank and evaporated in
this tank. The inorganic and organic materials are then simultaneously
deposited.

[0057]Preferably, the external tank which stores an organic material is
heated and evacuated, the organic material is supplied to the chamber,
and oxygen gas and/or argon gas is used to perform ion-assisted
deposition in view of deposition rate control. In the present invention,
the organic material is liquid at normal temperature and normal pressure.
The present invention does not need a solvent, and allows direct heating
and evaporation of the organic material. It is effective to arrange the
supply port of the organic material right above the inorganic material
vapor source to improve impact resistance and wear resistance. It is
preferable to supply the organosilicon compound upward and supply
downward the non-silicon-containing organic compound having a reactive
group at its side chain or terminal and containing carbon and hydrogen as
indispensable components.

[0058]The heating temperature of the external tank falls within the range
of 30 to 200° C. and preferably 50 to 150° C. to obtain an
appropriate deposition rate, depending on the vaporization temperatures
of organic materials.

[0059]The content of the organic material in the hybrid layer according to
the present invention falls within the range of 0.020 to 25 wt %
particularly in consideration of a better physical property improvement
effect.

[0060]The preferable film thickness and refractive index ranges of the
present invention are as follows. In this case, λ represents the
wavelength of light.

[0061]The above physical properties of the films can achieve the target
physical properties.

[0062]The uppermost water-repellent film layer 67 improves the smoothness
of the convex optical surface 2a and the concave optical surface 2b to
improve the antifouling property and prevent water stain. A super
water-repellent lens excellent in slide property is recently popular. A
water-repellent agent made from an organosilicon compound containing a
fluorine-substituted alkyl group is used as the water-repellent agent.

[0063]The material and formation method of the water-repellent film layer
67 preferably employ a method described in Japanese Patent Laid-Open No.
2004-122238. According to this method, the organosilicon compound
containing the fluorine-substituted alkyl group diluted with a solvent is
set in a reduced pressure. The process from the start of heating to the
deposition is preferably finished within 90 sec and preferably 10 sec in
the temperature range equal to or higher than the deposition start
temperature of this organosilicon compound and not exceeding its
decomposition temperature. A method which achieves this deposition time
range is preferably a method which irradiates the organosilicon compound
with an electron beam.

[0064]A compound represented by general formula (h) or unit formula (i) is
preferably used as the organosilicon compound containing the
fluorine-substituted alkyl group.

##STR00007##

[0065]In general formula (h), RF represents a straight chain
perfluoroalkyl group having 1 to 16 carbon atoms, X represents hydrogen
or a lower alkyl group having 1 to 5 carbon atoms, R11 represents a
hydrolyzable group, k is an integer of 1 to 50, r is an integer of 0 to
2, and p is an integer of 1 to 10.

CqF2q+1CH2CH2Si(NH2)3 (i)

[0066]wherein q is an integer of 1 or more.

[0067]Examples of the hydrolyzable group represented by R11 include
an amino group, an alkoxy group particularly an alkoxy group including an
alkyl part having 1 to 2 carbon atoms, and a chlorine atom.

[0069]The material of the water-repellent film layer 67 may contain as two
major components the organosilicon compound containing the
fluorine-substituted alkyl group and perfluoropolyether not containing
silicon. In addition, a first layer may be formed from these major
components, and a second layer may be formed on the first layer using a
material containing as a major component perfluoropolyether not
containing silicon, thereby forming the water-repellent film layer.

[0070]The perfluoropolyether not containing silicon preferably employs a
compound consisting of a unit having the following structural formula:

--(R12O)-- (j)

In formula (j), R12 represents a perfluoroalkylene group having 1 to
3 carbon atoms. The average molecular weight falls within the range of
1,000 to 10,000 and more preferably 2,000 to 10,000. R represents a
perfluoroalkylene group having 1 to 3 carbon atoms, and its specific
examples include groups such as CF2, CF2--CF2,
CF2CF2CF2, and CF(CF2)CF2. These
perfluoropolyethers are liquid at normal temperature and called fluorine
oils.

[0071]In the spectacle lens of the present invention, a layer made from at
least one metal selected from metals having a catalyst function in
forming a hybrid layer (to be described later), such as nickel (Ni),
silver (Ag), platinum (Pt), niobium (Nb), and titanium (Ti) can be formed
as an underlayer below an antireflection film layer in order to improve
the bonding property. The most preferable underlayer is a metal layer
made from niobium to impart better impact resistance. Use of the metal
layer as the underlayer enhances the reaction with the hybrid layer
formed on the underlayer, thereby obtaining a material having an
intra-molecular network structure and improving the impact resistance.

[0072]According to the present invention, it is also preferable to form a
double layer structure inside the uppermost water-repellent film layer
67, i.e., the first and second water-repellent layers. For example, a
vapor material containing a mixture of the organosilicon compound
containing the fluorine-substituted alkyl group represented by general
formula (I) and at least one silane compound selected from the following
general formulas (II-1), (II-2), and (II-3) is deposited on the optical
member to form the first water-repellent layer. The resultant structure
is dipped in a dipping material containing a solvent and
perfluoropolyether-polysiloxane copolymer modified silane represented by
general formula (III) to form the second water-repellent layer, thereby
forming a water-repellent film layer 67 made from the two layers.

##STR00008##

[0073]In general formula (I), Rf represents a divalent group which
includes a unit represented by formula --(CkF2kO)-- (wherein k
is an integer of 1 to 6) and has an unbranched straight chain
perfluoropolyalkylene ether structure. R independently represents a
monovalent hydrocarbon group having 1 to 8 carbon atoms. X independently
represents a hydrolyzable group or halogen atom, n and n' each represent
an integer of 0 to 2, m and m' each represent an integer of 1 to 5, and a
and b each represent 2 or 3.

[0074]General Formula (II)

[Chemical 9]

R'--Si(OR'')3 General formula (II-1)

Si(OR'')4 General formula (II-2)

SiO(OR'')3Si(OR'')3 General formula (II-3)

[0075]wherein R' represents an organic group and R'' represents an alkyl
group.

##STR00009##

[0076]In general formula (III), Rg represents a divalent group which
includes a repeating unit represented by formula --(CjF2jO)--
(wherein j is an integer of 1 to 5) and has an unbranched straight chain
perfluoropolyalkylene ether structure. The repeating unit count is 30 to
60. Different j repeating units may be simultaneously included. R1
represents the same or different alkyl groups or phenyl groups having 1
to 4 carbon atoms, w is 30 to 100, and a, b, and c each independently
represent an integer of 1 to 5. R2 represents an alkyl group or
phenyl group having 1 to 4 carbon atoms, X1 represents a
hydrolyzable group, d is 2 or 3, and y is an integer of 1 to 5.

[0077]The compounds represented by general formulas (I) to (III) will be
described below.

[0078]In general formula (I), the Rf group is a divalent group which
includes a unit represented by formula --(CkF2kO)-- (wherein k
is an integer of 1 to 6 and preferably 1 to 4, and the sequence of
CkF2kO in general formula (I) is random) and has an unbranched
straight chain perfluoropolyalkylene ether structure. Note that when both
n and n' in general formula (I) are zero, the terminal of the Rf group
bonded to the oxygen atom (O) in general formula (I) is not an oxygen
atom:

[0079]wherein Rf represents a divalent straight chain perfluoropolyether
group and include perfluoropolyether groups having a variety of chain
lengths. Rf preferably represents a divalent straight chain
perfluoropolyether having a perfluoropolyether having 1 to 6 carbon atoms
as the repeating unit. Examples of this divalent straight chain
perfluoropolyether are as follows:

--CF2CF2O(CF2CF2CF2O)rCF2CF2--

--CF2(OC2F4)s--(OCF2)t--

wherein r, s, and t each represent an integer of 1 or more. More
specifically, r, s, and t each fall within the range of 1 to 50 and more
preferably 10 to 40. Note the perfluoropolyether molecular structure is
not limited to the exemplified structures.

[0080]In general formula (I), X represents a hydrolyzable group or halogen
atom. Examples of X as the hydrolyzable group include an alkoxy group
such as a methoxy group, ethoxy group, propoxy group, or butoxy group; an
alkoxyalkoxy group such as a methoxymethoxy group, methoxyethoxy group,
or ethoxyethoxy group; an alkenyloxy group such as an allyloxy group or
isopropenoxy group; an asiloxy group such as an acetoxy group,
propyonyloxy group, butylcarbonyloxy group, or benzoyloxy group; a
ketoxime group such as a dimethylketoxime group, methylethylketoxime
group, diethylketoxime group, cyclopentanoxime group, or cyclohexanoxime
group; an amino group such as an N-methylamino group, N-ethylamino group,
N-propylamino group, N-butylamino group, N,N-dimethylamino group,
N,N-diethylamino group, or N-cyclohexylamino group; an amide group such
as an N-methylacetoamide group, N-ethylacetoamide group, or
N-methylbenzamide group; and an aminooxy group such as an
N,N-dimethylaminooxy group or N,N-diethylaminooxy group.

[0081]Examples of X as the halogen atom include a chlorine atom, bromine
atom, and iodine atom.

[0082]Among them all, the methoxy group, ethoxy group, isopropenoxy group,
and chlorine atom are most preferable.

[0083]In general formula (I), R represents a monovalent hydrocarbon group
having 1 to 8 carbon atoms. If R represents a plurality of monovalent
hydrogen groups, they may be the same or different. Specific examples of
R include an alkyl group such as a methyl group, ethyl group, propyl
group, butyl group, pentyl group, hexyl group, heptyl group, or octyl
group; a cycloalkyl group such as a cyclopentyl group or cyclohexyl
group; an aryl group such as a phenyl group, tolyl group, or xylyl group;
an aralkyl group such as a benzyl group or phenetyl group; and an alkenyl
group such as a vinyl group, allyl group, butenyl group, pentenyl group,
or hexenyl group. Among them all, a monovalent hydrocarbon group having 1
to 3 carbon atoms is preferable, and the methyl group is most preferable.

[0084]In general formula (I), n and n' each represent an integer of 0 to 2
and preferably 1, and may be the same or different, m and m' each
represent an integer of 1 to 5, preferably 3, and may be the same or
different.

[0085]Next, a and b each represent 2 or 3 and preferably 3 in view of
hydrolysis, condensation reactivity, and bonding property.

[0086]The molecular weight of the organosilicon compound containing the
fluorine-substituted alkyl group represented by general formula (I) is
not particularly limited, but its number average molecular weight
appropriately falls within the range of 500 to 20,000 and preferably
1,000 to 10,000 in view of stability and handling.

[0087]Specific examples of the organosilicon compound containing the
fluorine-substituted alkyl group represented by structural formula (I)
are as follows, but are not limited to the exemplified compounds.

[0088]The compound represented by general formula (I) can be used singly
or in a combination of two or more compounds. In some case, the
organosilicon compound containing the fluorine-substituted alkyl group
and its partial hydrolyzed condensate can be combined and used. In
addition, perfluoropolyether-polysiloxane copolymer modified silane
represented by general formula (III) can be combined and used with the
compound represented by general formula (I).

[0089]The organosilicon compound containing the fluorine-substituted alkyl
group represented by general formula (I) is preferably diluted with a
solvent. Examples of a solvent to be used include a fluorine-modified
aliphatic hydrocarbon solvent (e.g., perfluoroheptane or
perfluorooctane), a fluorine-modified aromatic hydrocarbon solvent (e.g.,
1,3-di(trifluoromethyl)benzene or trifluoromethylbenzene), a
fluorine-modified ether solvent (e.g., methylperfluorobutyl ether or
perfluoro(2-butyltetrahydrofurane), a fluorine-modified alkylamine
solvent (e.g., perfluorotributylamine or perfluorotripentylamine), a
hydrocarbon solvent (e.g., petroleum benzene, mineral spirits, toluene,
or xylene), a ketone solvent (e.g., acetone, methyl ethyl ketone, or
methyl isobutyl ketone), and an alcohol solvent (methanol, ethanol,
isopropanol, or n-propanol). These solvents can be used singly or in a
combination of two or more solvents. Among them all, a fluorine-modified
solvent is preferable in view of the dissolvability and wettability of
modified silane. Examples of the most preferable solvent include
1,3-di(trifluoromethyl)benzene, perfluoro(2-butyltetrahydrofurane), and
perfluorotributylamine.

[0090]One silane compound selected from the general formulas (II-1),
(II-2), and (II-3) comprises the following:

R'--Si(OR'')3 General formula (II-1)

Si(OR'')4 General formula (II-2)

SiO(OR'')3Si(OR'')3 General formula (II-3)

[0091]wherein R' represents an organic group. Examples of R' include an
alkyl group (e.g., a methyl group, ethyl group, or propyl group) having 1
to 50 carbon atoms (preferably 1 to 10 carbon atoms), an epoxyethyl
group, a glycidyl group, and an amino group. These groups may be
substituted. R'' represents an alkyl group (e.g., a methyl group, ethyl
group, or propyl group) having 1 to 48 carbon atoms and is preferably a
methyl group or ethyl group.

[0092]Specific examples of the silane compounds represented by general
formulas (II-1) to (II-3) include structural formulas
(C2H5O)3SiC3H6NH2,
(CH3O)3SiC3H6NH2, (C2H5O)4Si, and
(C2H5O)3Si--O--Si(OC2H5)3. However, the
silane compound is not limited to the above examples.

[0093]The silane compounds represented by general formulas (II-1) to
(II-3) can be used singly or in a combination of two or more silane
compounds.

[0094]The silane compound preferably contains the compound represented by
general formula (II-1) singly or in an amount larger than those of other
components.

[0096]In general formula (III), the Rg group is a divalent group which
includes repeating unit represented by formula --(CjF2jO)--
(wherein j is an integer of 1 to 5 and preferably 1 to 3, and the
sequence of CjF2jO in general formula (III) is random) and has
an unbranched straight chain perfuluoropolyalkylene ether structure. The
repeating unit count is 30 to 60 (preferably 30 to 50). Different j
repetition counts may be simultaneously included:

[0097]wherein Rg represents a divalent straight chain perfluoropolyether
group and include perfluoropolyether groups having a variety of chain
lengths. Rg preferably represents a divalent straight chain
perfluoropolyether having a perfluoropolyether having about 1 to 5 carbon
atoms as the repeating unit. Examples of this divalent straight chain
perfluoropolyether are as follows:

--CF2CF2O(CF2CFCF2O)kCF2CF2--

--CF2(OC2F4)p--(OCF2)q--

wherein k, p, and q each represent an integer of 1 or more, and k and p+q
preferably fall within the range of 30 to 60. Note the perfluoropolyether
molecular structure is not limited to the exemplified structures.

[0098]In general formula (III), R1 represents an alkyl group (e.g., a
methyl group, ethyl group, propyl group, or butyl group) or phenyl group
having 1 to 4 carbon atoms. The alkyl groups or phenyl groups may be the
same or different.

[0099]In general formula (III), w is 30 to 100 and preferably 30 to 60,
and a, b, and c each independently represent an integer of 1 to 5 and
preferably 1 to 3.

[0100]In general formula (III), R2 represents an alkyl group (e.g., a
methyl group, ethyl group, propyl group, or butyl group) or phenyl group
having 1 to 4 carbon atoms.

[0101]In general formula (III), X1 represents a hydrolyzable group.
Examples of X1 include an alkoxy group such as a methoxy group,
ethoxy group, propoxy group, or butoxy group; an alkoxyalkoxy group such
as a methoxymethoxy group, methoxyethoxy group, or ethoxyethoxy group;
alkenyloxy group such as an allyloxy group or isopropenoxy group; an
acyloxy group such as an acetoxy group, propionyloxy group,
butylcarbonyloxy group, or benzoyloxy group; a ketoxime group such as a
dimethylketoxime group, methylethylketoxime group, diethylketoxime group,
cyclopentanoxime group, or cyclohexanoxime group; an amino group such as
an N-methylamino group, N-ethylamino group, N-propylamino group,
N-butylamino group, N,N-dimethylamino group, N,N-diethylamino group, or
N-cyclohexylamino group; an amide group such as an N-methylacetoamide
group, N-ethylacetoamide group, or N-methylbenzamide group; and an
aminooxy group such as an N,N-dimethylaminooxy group or
N,N-diethylaminooxy group. Among them all, the methoxy group, ethoxy
group, and isopropynoxy group are preferable.

[0102]In general formula (III), d is 2 or 3 and preferably 3 in
consideration of hydrolysis, condensation reactivity, and film bonding
property, and y is an integer of 1 to 5 and preferably 1 to 3.

[0103]The compounds represented by general formula (III) can be used
singly or in a combination of two or more compounds.

[0104]The material of the plastic base member used in the present
invention is not limited to a specific material. Examples of the plastic
base member include a methyl methacrylate homopolymer, a copolymer formed
from methyl methacrylate and at least another monomer, a homopolymer made
from diethylene glycol bisallylcarbonate, a copolymer formed from
diethylene glycol bis(allyl carbonate) and at least another monomer, a
sulfur-containing copolymer, a halogen copolymer, and a polymer using as
a material a compound including polycarbonate, polystyrene, polyvinyl
chloride, unsaturated polyester, polyethylene terephtalate, polyurethane,
polythiourethane, or epithio group.

[0105]Examples of the compound having the epithio group include chain
organic compounds such as bis(β-epithiopropylthio)metane,
1,2-bis(β-epithiopropylthio)ethane,
1,3-bis(β-epithiopropylthio)propane,
1-2-(β-epithiopropylthio)propane,
1-(β-epithiopropylthio)-2-(β-epithiopropylthio)propane,
1,4-bis(β-epithiopropylthio)butane,
1,3-bis(β-epithiopropylthio)butane,
1-(β-epithiopropylthio)-3-(β-epithiopropylthiomethyl)butane,
1,5-bis(β-epithiopropylthio)pentane,
1-(β-epithiopropylthio)-4-(β-epithiopropylthiomethyl)pentane,
1,6-bis(β-epithiopropylthio)hexane,
1-(β-epithiopropylthio)-5-(β-epithiopropylthiomethyl)hexane,
1-(β-epithiopropylthio)-2-[(2-β-epithiopropylthioethyl)thio]eth-
ane, and 1-(β-epithiopropylthio)-2-[[2-(2-β-epithiopropylthioeth-
yl)thioethyl]thio]ethane. Examples of the compound having the epithio
group also include branched organic compounds and compounds obtained by
substituting at least one hydrogen of the episulfide group of each of
these compounds with a methyl group. Specific examples of the branched
organic compounds include
tetrakis(β-epithiopropylthiomethyl)methane,
1,1,1-tris(β-epithiopropylthiomethyl)propane,
1,5-bis(β-epithiopropylthio)-2-(β-epithiopropylthiomethyl)-3-th-
iapentane, 1,5-bis(β-epithiopropylthio)-2,4-bis(β-epithiopropylt-
hiomethyl)-3-thiopentane,
1-(β-epithiopropylthio)-2,2-bis(β-epithiopropylthiomethyl)-4-th-
iahexane, 1,5,6-tris(β-epithiopropylthio)-4-(β-epithiopropylthio-
methyl)-3-thiahexane,
1,8-bis(β-epithiopropylthio)-4-(β-epithiopropylthiomethyl)-3,6--
dithiaoctane,
1,8-bis(β-epithiopropylthio)-4,5-bis(β-epithiopropylthiomethyl)-
-3,6-dithiaoctane,
1,8-bis(β-epithiopropylthio)-4,4-bis(β-epithiopropylthiomethyl)-
-3,6-dithiaoctane,
1,8-bis(β-epithiopropylthio)-2,4,5-tris(β-epithiopropylthiometh-
yl)-3,6-dithiaoctane,
1,8-bis(β-epithiopropylthio)-2,5-bis(β-epithiopropylthiomethyl)-
-3,6-dithiaoctane,
1,9-bis(β-epithiopropylthio)-5-(β-epithiopropylthiomethyl)-5-[(-
2-β-epithiopropylthioethyl)thiomethyl]-3,7-dithianonane,
1,10-bis(β-epithiopropylthio)-5,6-bis[(2-(β-epithiopropylthioet-
hyl)thio]-3,6,9-trithiadecane,
1,11-bis(β-epithiopropylthio)-4,8-bis(β-epithiopropylthiomethyl-
)-3,6,9-trithiaundecane,
1,11-bis(β-epithiopropylthio)-5,7-bis(β-epithiopropylthiomethyl-
)-3,6,9-trithiaundecane,
1,11-bis(β-epithiopropylthio)-5,7-[(2-(β-epithiopropylthioethyl-
)thiomethyl]-3,6,9-trithiaundecane, and
1,11-bis(β-epithiopropylthio)-4,7-bis(β-epithiopropylthiomethyl-
)-3,6,9-trithiaundecane. Examples of the compound having the epithio group
further include alicyclic organic compounds and compounds obtained by
substituting at least one hydrogen of the episulfide group of each of
these compounds with a methyl group, and aromatic organic compounds and
compounds obtained by substituting at least one hydrogen of the
episulfide group of each of these compounds with a methyl group. Specific
examples of the alicyclic organic compound include 1,3- and
1,4-bis(β-epithiopropylthio)cyclohexane, 1,3- and
1,4-bis(β-epithiopropylthiomethyl)cyclohexane,
bis[4-(β-epithiopropylthio)cyclohexyl]methane,
2,2-bis[4-(β-epithiopropylthio)cyclohexyl]propane,
bis[4-(β-epithiopropylthio)cyclohexyl]sulfide,
2,5-bis(β-epithiopropylthiomethyl)-1,4-dithiane, and
2,5-bis(β-epithiopropylthioethylthiomethyl)-1,4-dithiane. Specific
examples of the aromatic organic compound include 1,3- and
1,4-bis(β-epithiopropylthio)benzene, 1,3- and
1,4-bis(β-epithiopropylthiomethyl)benzene,
bis[4-(β-epithiopropylthio)phenyl]methane,
2,2-bis[4-(β-epithiopropylthio)phenyl]propane,
bis[4-(β-epithiopropylthio)phenyl]sulfide,
bis[4-(β-epithiopropylthio)phenyl)sulfone, and
4,4'-bis(β-epithiopropylthio)biphenyl.

[0106]Referring to FIGS. 1 and 4, the lens rotating shaft 4 includes first
and second lens rotating shafts 4A and 4B arranged horizontally such that
their axes coincide with each other, and is disposed in a lens holding
unit 15. The lens holding unit 15 has a pair of supports 15a and 15b
opposing each other in the horizontal direction (X direction) of the
apparatus. One support 15a axially, rotatably supports the first lens
rotating shaft 4A, and the other support 15b axially supports the second
lens rotating shaft 4B to be rotatable and movable in the axial
direction. As shown in FIG. 2, a lens holder 16 and lens retainer 17
constituting the lens holding means for the processing target lens 2 are
detachably attached to the opposing distal ends of the first and second
lens rotating shafts 4A and 4B, respectively.

[0107]A lens rotating shaft driving motor 18 is fixed to the other support
15b of the lens holding unit 15. The rotation of the driving motor 18 is
transmitted to the first and second lens rotating shafts 4A and 4B
through a rotation transmitting means 19 such as a pulley or toothed
belt. Therefore, the first and second lens rotating shafts 4A and 4B are
synchronously driven. As the lens rotating shaft driving motor 18, a
reversible pulse motor with a variable rotation speed is used. A driving
motor (not shown) which moves the second lens rotating shaft 4B
forward/backward with respect to the first lens rotating shaft 4A is
built in the other support 15b of the lens holding unit 15.

[0108]The first lens rotating shaft moving mechanism 5 includes a pair of
front and rear X-axis linear guides 31, an X-direction table 32, and an
X-direction table driving motor 33. The X-axis linear guides 31 are set
on a bottom plate 30 of the housing 3 to be parallel to each other and
are long in the X direction. The X-direction table 32 is movable in the X
direction along the X-axis linear guides 31. The X-direction table
driving motor 33 moves the X-direction table 32 along the X-axis linear
guides 31.

[0109]The second lens rotating shaft moving mechanism 6 includes a pair of
left and right Y-axis linear guides 35, a Y-direction table 36, a
Y-direction table driving motor 37, and the lens holding unit 15. The
Y-axis linear guides 35 are set on the upper surface of the X-direction
table 32 to be parallel to each other and extend in the Y direction. The
Y-direction table 36 is movable in the Y direction along the Y-axis
linear guides 35. The Y-direction table driving motor 37 moves the
Y-direction table 36 along the Y-axis linear guides 35. The lens holding
unit 15 is set on the Y-direction table 36. Thus, the operation of the
lens rotating shaft 4 includes movements in three directions, i.e.,
rotation about the axis, movement in the horizontal direction (X
direction) perpendicular to the axis, and movement in the back-and-forth
direction (Y direction). The controller numerically controls the
movements in the three directions based on the shape processing data on
the processing target lens 2.

[0110]As the processing tool 7 which grinds a circumferential surface 2c
of the processing target lens 2, a grinding stone such as a cylindrical
diamond wheel as shown in FIG. 2 is employed and attached to a processing
tool rotating shaft 40 of the rotational drive mechanism 8. The
processing tool 7 includes a primary processing (rough processing)
grinding wheel 7A and secondary processing (finishing) grinding wheel 7B.
A beveling groove 41 formed of an axi-symmetric V-shaped annular groove
is formed in the outer circumferential surface of the secondary
processing grinding wheel 7B.

[0111]The rotational drive mechanism 8 of the processing tool 7 includes a
frame 44, the processing tool rotating shaft 40, an inverter type
processing tool driving motor 45, and a rotation transmitting mechanism
46 such as a pulley or toothed belt. The frame 44 is set on the bottom
plate 30 of the housing 3. The processing tool rotating shaft 40 is
cantilevered at the upper end of the frame 44. The processing tool
driving motor 45 rotates the processing tool rotating shaft 40. The
rotation transmitting mechanism 46 transmits the rotation of the
processing tool driving motor 45 to the processing tool rotating shaft
40. The processing tool rotating shaft 40 is parallel to the lens
rotating shaft 4 and located in front of it.

[0112]As shown in FIG. 4, the lens shape measurement unit 9 includes a
pair of left and right measurement elements 50A and 50B, a driving motor
(not shown), and an arithmetic processing unit (not shown). The
measurement elements 50A and 50B are disposed to oppose each other and
trace the optical surfaces 2a and 2b of the processing target lens 2. The
driving motor moves the measurement elements 50A and 50B to be close to
and separate from each other. The arithmetic processing unit calculates
the positions of the optical surfaces 2a and 2b and those of the two
edges of each of the circumferential surface 2c and circumferential
surfaces 2d and 2e, i.e., convex peripheral edges 51A, 52A, and 53A and
concave peripheral edges 51B, 52B, and 53B, of the processing target lens
2 from the traces of the measurement elements 50A and 50B, and measures
shape information on the processing target lens 2. In FIG. 4, reference
numeral 2c denotes the circumferential surface of the processing target
lens 2 before edging; 2d, the circumferential surface after primary
processing; and 2d, the circumferential surface after secondary
processing.

[0113]When measuring the shape of the processing target lens 2 by the lens
shape measurement unit 9, the processing target lens 2 is rotated. The
left and right measurement elements 50A and 50B are moved close to each
other and urged against the optical surfaces 2a and 2b, respectively, of
the processing target lens 2. In this state, the lens holding unit 15 is
moved back and forth. Then, the shape of the processing target lens 2 can
be measured.

[0114]The chamfering mechanism 10 chamfers the edge portions 53A and 53B
of the processing target lens 2 after secondary processing, and includes
a pair of left and right chamfering tools 60, a chamfering driving motor
61, and a rotation transmitting mechanism 62 such as a pulley or belt.
The chamfering driving motor 61 drives the chamfering tools 60. The
rotation transmitting mechanism 62 transmits the rotation of the
chamfering driving motor 61 to the chamfering tools 60. As the chamfering
tools 60, grinding tools such as diamond wheels are employed.

[0115]The procedure of edging the processing target lens 2 by the
spectacle lens edging apparatus 1 having the above structure will be
described based on the flowchart shown in FIG. 7.

[0116]First, the optician as the order placing side transmits information
on a spectacle lens needed by the manufacturer to the lens manufacturer's
factory as the manufacturing side in an online manner (step S1). When
requesting manufacture and delivery of the lens to the factory, the
optician sends to the factory various types of information such as the
material and prescription values of the lens, the specified processing
values of the lens, spectacle frame information, layout information which
specifies the eye point position, the bevel mode, the bevel position, and
the bevel shape that are necessary for the lens manufacture. The
spectacle frame information includes 3-dimensional lens frame shape data,
approximate curved surface definition data, a frame PD (or DBL), an
optical axis angle, and the circumferential length.

[0117]This request for manufacturing the spectacle lens from the optician
to the factory is effective particularly when, e.g., requesting the
manufacture of a lens having a water-repellent film layer (because
primary processing by the optician is difficult if a water-repellent film
layer is formed on the lens).

[0118]At the factory, upon acquiring various types of information
necessary for the manufacture of the spectacle lens from the optician,
processing shape data, edged lens shape information, layout information,
processing designation information and the like are created based on the
acquired information, and input to the edging apparatus 1 (step S2).

[0119]Subsequently, the operator selects among uncut lenses stored as the
stock a lens complying with the ordered lens as the processing target
lens 2 and holds the optical surface 2a of the selected lens 2 using the
lens holder 16 (step S3).

[0120]As shown in FIG. 3, the lens holder 16 includes a metal shaft
portion 70 and a holding cup 71 which is integrally molded with the shaft
portion 70 and made of an elastic material. The holding cup 71 includes a
shaft portion 71A fixed to the shaft portion 70 and a lens holding
portion 71B integrally provided to the distal end face of the shaft
portion 71A. The lens holding portion 71B forms a rectangular plate. The
front surface of the lens holding portion 71B forms a lens holding
surface 72. The lens holding surface 72 forms a concave surface with a
radius of curvature almost equal to that of the convex optical surface 2a
of the lens 2. A leap tape 73 is adhered to the lens holding surface 72.
When holding the processing target lens 2 using the lens holder 16, the
leap tape 73 may be adhered to the convex optical surface 2a by urging.
At this time, the lens holder 16 is attached to the processing target
lens 2 such that its center O coincides with a processing center position
21 serving as the rotation center of the processing target lens 2 when
processing the processing target lens 2, as shown in FIG. 5A. If the lens
includes a cylinder axis, the lens holder 16 is attached to the lens by
setting the cylinder axis at a predetermined angle. The processing center
position 21 of the processing target lens 2 coincides with a frame center
B of the spectacle frame, or an optical center C of the processing target
lens 2.

[0121]The operator displays two axial deviation measuring marks 81a and
81b (FIGS. 5A to 5C) on the convex optical surface 2a of the processing
target lens 2 (step S4). Two reference position marks 80a and 80b are
displayed on the lens holder 16 in advance, and the axial deviation
measuring marks 81a and 81b are displayed to coincide with the marks 80a
and 80b. The reference position marks 80a and 80b of the lens holder 16
include two perpendicular straight lines extending through the center O
and are displayed on the rear surface of the lens holding portion 71B.
The reference position marks 80a and 80b are displayed on the lens holder
16 in advance before the processing target lens 2 is held. However, the
present invention is not limited to this. The reference position marks
80a and 80b and axial deviation measuring marks 81a and 81b may be
simultaneously displayed on the lens holder 16 and processing target lens
2 after the processing target lens 2 is held.

[0122]The axial deviation measuring marks 81a and 81b of the processing
target lens 2 include two perpendicular straight lines extending through
the processing center position 21. After the lens holder 16 holds the
lens 2, the axial deviation measuring marks 81a and 81b are displayed
using an appropriate ink such that they form straight lines continuous
with the reference position marks 80a and 80b. The marks 81a and 81b have
different line widths. One mark 81a has a larger line width than that of
the other mark 81b.

[0123]The processing target lens 2 is mounted on the lens rotating shaft 4
(step S5). When mounting the processing target lens 2 on the lens
rotating shaft 4, first, the lens holder 16 which holds the processing
target lens 2 is mounted on the first lens rotating shaft 4A. The lens
holder 16 can be mounted by fitting the shaft portion 70 in a recess
formed in the distal end face of the first lens rotating shaft 4A.

[0124]Subsequently, the second lens rotating shaft 4B is moved forward to
urge the lens retainer 17 attached to the distal end of the lens rotating
shaft against the concave optical surface 2b of the processing target
lens 2 through an elastic member 85 (FIG. 2). Thus, the lens holder 16
and lens retainer 17 sandwich and hold the processing center positions 21
of the convex and concave optical surfaces 2a and 2b of the processing
target lens 2, thus completely mounting the lens on the lens rotating
shaft 4.

[0125]Then, the lens rotating shaft 4 is rotated at a low speed, and the
circumferential surface 2c of the processing target lens 2 undergoes
primary processing by the processing tool 7 based on the processing shape
data (step S6). In primary processing, the primary processing grinding
wheel 7A grinds the circumferential surface 2c to form the processing
target lens 2 into a primary shape. The primary shape of the processing
target lens 2 obtained by primary processing is either a circle larger
than a circle inscribed by the edged lens shape 2A (FIGS. 5A to 5C) that
complies with the frame shape of the spectacle frame, or an edged shape
similar to the edged lens shape 2A and larger than it by the processing
margin of secondary processing. A circle 88 larger than the circle
inscribed by the edged lens shape 2A is a circle having a radius (e.g.,
50 mm) equal to or slightly larger than a value obtained by adding the
processing margin of secondary processing to a maximum radius R (FIG. 5B)
of the edged lens shape 2A.

[0126]When primary processing of the processing target lens 2 is ended,
the operator removes it from the lens rotating shaft 4 and measures its
axial deviation (step S7). Assume that the processing target lens 2 has a
water-repellent film layer. If the processing target lens 2 undergoes
primary processing while it is held by a lens holding force almost equal
to that for a general lens, as the processing resistance is large, axial
deviation occurs easily. If secondary processing is performed with the
axial deviation uncorrected, the lens becomes defective.

[0127]In view of this, after primary processing is ended, the lens holder
16 is removed from the first lens rotating shaft 4A, and whether axial
deviation exists or not is checked from the reference position marks 80a
and 80b and axial deviation measuring marks 81a and 81b.

[0128]FIG. 5B shows a case in which, as the result of primary processing,
the processing center position 21 axially deviates from the center O of
the lens holder 16 by -X1 in the X direction and by -Y1 in the
Y direction and the rotation angle axially deviates counterclockwise by
-θ1 with respect to the reference position mark 80a. FIG. 5C
shows a case in which the processing center position 21 does not axially
deviate with respect to the center O of the lens holder 16 and only the
rotation angle axially deviates counterclockwise by θ2 with
respect to the reference position mark 80a.

[0129]When axial deviation exists, the deviation amounts X1 and
Y1 in the X and Y directions of the processing center position 21
with respect to the center O of the lens holder 16, and the rotation
angle θ1 or θ2 are measured. As the result of axial
deviation measurement, if the deviation amounts of the processing center
position 21 in the X and Y directions are ±0.5 mm or more, or if the
rotation angle is ±5° or more, it is determined that the
processing center position 21 axially deviates. Otherwise, it is
determined that axial deviation does not exist. The allowable values of
the axial deviation amounts and rotation angle differ depending on the
type and dioptric power of the lens. For example, when the target lens is
a single-vision lens having a cylinder axis, if the deviation of the
rotation angle described above is ±2° or less, the
specifications of the spectacle lens may be satisfied. The tolerance is
accordingly selected appropriately.

[0130]This axial deviation measurement is performed by the operator
visually, or by known image processing. When image processing is
employed, it is advantageous because the deviation amount can be measured
more accurately than by visual measurement. Correction of processing
shape data by means of image processing will further be described later.

[0131]As the result of measurement, when it is determined that axial
deviation exists, the processing target lens 2 is held again by the lens
holder 16, and the axial deviation is corrected (in step S8). More
specifically, the lens holder 16 is removed from the processing target
lens 2. The lens holder 16 is then mounted again on the processing target
lens 2 such that the center O of the lens holder 16 coincides with the
processing center position 21 of the processing target lens 2 and that
the reference position marks 80a and 80b coincide with the axial
deviation measuring marks 81a and 81b. This corrects the axial deviation.
If the axial deviation is equal to or less than the allowable value, the
lens holder 16 need not be removed from the processing target lens 2.

[0132]Subsequently, the processing target lens 2 is mounted on the lens
rotating shaft 4 again in accordance with the same procedure as in step
S5 described above (step S9).

[0133]After the processing target lens 2 is mounted on the lens rotating
shaft 4, the lens rotating shaft 4 is rotated, and the circumferential
surface 2d of the processing target lens 2 that has been primarily
processed undergoes secondary processing by the secondary processing
grinding wheel 7B into a secondary shape based on the processing shape
data (step S10). The secondary shape of the processing target lens 2 by
secondary processing is an edged lens shape that complies with the edged
lens shape 2A of the spectacle frame, or an edged lens shape slightly
larger than this. The edged lens shape slightly larger than that of the
spectacle frame is aimed at reserving, based on the order from the
optician, a processing margin necessary when the optician performs
finishing. The secondary shape of the processing target lens by secondary
processing is calculated in advance in the same manner as the primary
shape and input to the controller as processing shape data.

[0134]This embodiment employs the grinding wheel 7B having the beveling
groove 41, because it is aimed at the manufacture of a spectacle lens to
be mounted on a general rimmed spectacle frame. When manufacturing a
spectacle lens to be mounted on a spectacle frame not having a rim
(rimless spectacle) or a spectacle lens to be mounted on a nylol frame,
the circumferential surface of the processing target lens 2 may be edged
by exchanging the grinding wheel 7B for a grinding wheel for a rimless
spectacle frame or nylol frame.

[0135]When secondary processing is ended, the processing target lens 2 is
removed from the lens rotating shaft 4, and its axial deviation is
measured (step S11). The axial deviation is determined in accordance with
whether or not the reference position marks 80a and 80b deviate from the
axial deviation measuring marks 81a and 81b in the same manner as in step
S7 described above. In secondary processing, the processing target lens 2
which has undergone primary processing and thus has a small diameter is
to be processed. Therefore, even if the lens has a low processing
resistance and is formed with a water-repellent film layer, axial
deviation rarely occurs, or can be suppressed within the predetermined
allowable value range. Thus, highly accurate processing can be performed.
When the operator visually confirms that the axial deviation measuring
marks 81a and 81b do not deviate from the reference position marks 80a
and 80b, it can guarantee that the processing target lens 2 is free from
axial deviation.

[0136]When secondary processing is ended, chamfering is performed (step
S12). Chamfering is performed by rotating the processing target lens 2
together with the lens rotating shaft 4 and urging the chamfering tools
60 against the edge portions 53A and 53B of the circumferential surface
2e. The chamfering trace data of the chamfering tools 60 which are used
as the control data of the chamfering tools 60 during chamfering are
calculated based on position data of the edge portions 53A and 53B of the
circumferential surface 2e of the processing target lens 2 which are
calculated after secondary processing.

[0137]When chamfering is ended, the processing target lens 2 is removed
from the lens rotating shaft 4, and optical performance and appearance
test is performed (step S13).

[0138]A processing target lens 2 determined as an acceptable product is
packaged as a spectacle lens and delivered to the optician who placed the
order (step S14).

[0139]Upon reception of the spectacle lens from the factory, the optician
tests its optical performance and appearance. When the optician
determines that the spectacle lens is appropriate, if the spectacle lens
has an edged lens shape complying with the frame shape of the spectacle
frame selected by the user, the optician fits the lens in the spectacle
frame and delivers the spectacle frame to the user. If the spectacle lens
has an edged lens shape slightly larger than the frame shape of the
spectacle frame, the optician finishes the lens so as to comply with the
frame shape of the spectacle lens and fits it in the spectacle frame, and
delivers the spectacle frame to the user. In finishing by the optician,
since the shape of the lens itself is small and accordingly the
processing resistance is low, even if the lens is formed with a
water-repellent film layer, the lens rarely deviates axially.

[0140]In this manner, in this embodiment, the step of correcting the axial
deviation of the processing target lens includes the axial deviation
measuring step of removing the processing target lens from the lens
rotating shaft together with the lens holding means after primary
processing and measuring the axial deviation of the processing target
lens from the reference position mark and the axial deviation measuring
mark, the axial deviation correcting step of correcting the axial
deviation of the processing target lens which is measured by the axial
deviation measuring step by holding one optical surface of the processing
target lens with the lens holding means again such that the axial
deviation measuring mark coincides with the reference position mark, and
the step of mounting the lens holding means on the lens rotating shaft
again together with the processing target lens. Thus, in secondary
processing, the lens can be processed without causing axial deviation, in
the same manner as a general lens. More specifically, this embodiment
allows axial deviation of the processing target lens 2 in primary
processing. If the processing target lens 2 axially deviates due to
primary processing, the amount and direction of the axial deviation are
measured, and the axial deviation is corrected by holding the processing
target lens 2 again by the lens holder 16. When the axial deviation of
the processing target lens 2 is corrected in this manner in secondary
processing, since the shape of the lens itself in secondary processing is
small, even when the lens has a water-repellent film layer, the axial
deviation amount can be suppressed within the allowable value range
without holding the lens with a particularly large lens holding force.
Hence, even when the processing target lens 2 is a highly lubricant lens
or an uncut lens having a large diameter in primary processing, no
particular axial deviation preventive countermeasure is needed in the
primary processing step. Such a lens can be processed highly accurately
without causing axial deviation in the same manner as a general lens,
even if the lens is not held with a particularly large lens holding
force.

[0141]FIG. 8 is a flowchart showing another embodiment of the present
invention.

[0142]This embodiment is different from the embodiment described above in
terms of how axial deviation is corrected. More specifically, according
to the measurement and correction of axial deviation in this embodiment
(step S27), axial deviation is measured by image processing, and the
processing shape data itself of an edging apparatus 1 is corrected.

[0143]The procedure for this will be described hereinafter.

[0144]When measuring axial deviation by image processing, a line sensor 90
is arranged on a straight line extending through a center O of a lens
holder 16, as shown in FIG. 9. At least two reference position marks 80a
and 80b and axial deviation measuring marks 81a and 81b having different
line widths are displayed on the lens holder 16 and a processing target
lens 2 in advance to coincide with each other. When the marks 80a and 80b
and 81a and 81b have different line widths, the layout of the optical
center (C) on the processing target lens 2 in the mounted state can be
discriminated in the vertical and horizontal directions and the like.

[0145]When primary processing is ended, the processing target lens 2 is
removed from a lens rotating shaft 4 together with the lens holder 16,
and the line sensor 90 obtains the images of the reference position marks
80a and 80b and axial deviation measuring marks 81a and 81b. In obtaining
the images, the coordinate values of the reference position marks 80a and
80b and axial deviation measuring marks 81a and 81b are read by rotating
the processing target lens 2 in the direction of the arrow. If the marks
deviate, the deviation amounts are calculated; if do not, the processing
target lens 2 is mounted on the lens rotating shaft 4 again and undergoes
secondary processing.

[0146]When calculating the axial deviation amounts, the reference position
is determined on the center O of the lens holder 16 of a case in which
the marks do not deviate. In other words, the reference position is
determined on a position where straight lines extending from the two
reference position marks 80a and 80b of the lens holder 16 intersect. The
coordinate values of a point 21' where the straight lines extending from
the axial deviation measuring marks 81a and 81b on the processing target
lens 2 intersect are calculated, and the processing center position on
the processing target lens 2 resulted from the axial deviation is
specified (to be referred to as the processing center position 21'
hereinafter).

[0147]Subsequently, as the deviation amount in a direction perpendicular
to the lens rotating shaft 4, the distance and direction to the
processing center position 21' with reference to the center O of the lens
holder 16 are calculated and determined as a correction value A (X, Y).
The processing center position of the edging apparatus 1 expressed by the
correction value A is determined as the processing center 21' on the
processing target lens 2 deviating from the center O of the lens holder
16. As the deviation amount in the rotational direction, angles formed by
the respective axial deviation measuring marks 81a and 81b and reference
position marks 80a and 80b are calculated and determined as a correction
value B. The processing center of the processing shape data is corrected
based on the correction value A and correction value B, and secondary
processing is performed.

[0148]In this manner, after the axial deviation of the processing target
lens 2 is measured by image processing, the processing shaft center of
the processing shape data itself of the processing target lens 2 is
corrected, and secondary processing is performed based on the corrected
processing shape data. Then, even if the processing target lens 2
actually, axially deviates, it need not be removed from the lens holder
16 and held again by it. Thus, a fewer number of operation steps are
required than in the embodiment described above, and the time necessary
for edging can be shortened greatly, which is advantageous. Steps S21 to
S26 and steps S28 to S33 are completely the same as steps S1 to S6 and
steps S9 to S14 shown in FIG. 7, and a repetitive description thereof
will be omitted.

[0149]In this manner, according to this embodiment, the step of correcting
the axial deviation of the processing target lens comprises the step of
removing the processing target lens from the lens rotating shaft together
with the lens holding means after primary processing, measuring the axial
deviation of the processing target lens from the reference position mark
and the axial deviation measuring mark, and correcting the processing
shape data. In the secondary processing step, the processing target lens
is processed based on the processing shape data corrected by the
processing shape data correcting step. That is, the processing shape data
itself is corrected in accordance with the measured axial deviation
amount and its direction. Therefore, even when the processing target lens
axially deviates from the lens holding means, the lens need not be
removed from the lens holding means and held again by it, and can undergo
secondary processing in the axially deviating state. As a result, the
step of holding the lens again by the lens holding means to correct axial
deviation is not needed, and the time needed for lens edging can be
shortened.

[0150]According to this embodiment, the primary shape of the processing
target lens processed by the primary processing step is either one of a
circle larger than a circle inscribed by the edged lens shape that
complies with the frame shape of the spectacle frame and an edged shape
similar to this edged lens shape and larger than this. The secondary
shape of the processing target lens processed by the secondary processing
step is either one of an edged lens shape that complies with the frame
shape of the spectacle frame and an edged lens shape slightly larger than
that.

[0151]According to this embodiment, the axial deviation measuring step can
be performed by either one of image processing and visual measurement.

[0152]Furthermore, according to this embodiment, the reference position
mark can be displayed either before holding the processing target lens or
simultaneously with displaying the axial deviation measuring mark on the
unprocessed lens.

[0153]In the embodiment described above, the processing target lens is
delivered to the optician after it undergoes secondary processing into an
edged lens shape complying with the frame shape of the spectacle frame
selected by the user, or into an edged lens shape slightly larger than
the frame shape. Depending on the request of the optician, a processing
target lens having a primary shape, which has undergone only primary
processing, may be delivered. In this case, if the lens has axial
deviation, the optician is informed of the axial deviation amount and its
direction in addition to the processing center position 21'. Upon
reception of the processing target lens that has undergone primary
processing, the optician finishes the processing target lens into a shape
complying with the frame shape of the spectacle frame by holding the
processing center position 21, and fits the processed lens into the
spectacle frame, thus completing a spectacle.

INDUSTRIAL APPLICABILITY

[0154]The edging method according to the present invention is usefully
employed in edging a spectacle lens.